Make batter: Put butter and chocolate in a heatproof medium bowl set over a pan of simmering water; stir until melted. Let cool slightly.

• 制作奶油面糊：将黄油、巧克力放入一只不怕烫的中等碗中。取一只锅，其中放入热水，把碗置于其中；搅拌碗中食物直至融化。放在一边冷却。